Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> writes: > Right now, the BO is mapped as a cached region when ->vmap() is called > and the underlying object is not a dmabuf. > Doing that makes cache management a bit more complicated (you'd need > to call dma_map/unmap_sg() on the ->sgt field everytime the BO is about > to be passed to the GPU/CPU), so let's map the BO with writecombine > attributes instead (as done in most drivers). > > Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> > --- > Found this issue while working on panfrost perfcnt where the GPU dumps > perf counter values in memory and the CPU reads them back in > kernel-space. This patch seems to solve the unpredictable behavior I > had. > > I can also go for the other option (call dma_map/unmap/_sg() when > needed) if you think that's more appropriate. writecombined was the intent, and this makes kernel vmap match the userspace mmap path. Reviewed-by: Eric Anholt <eric@xxxxxxxxxx>
Attachment:
signature.asc
Description: PGP signature
_______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
